afaik fF uses an old exploit that has been patched, and it's delivery method is somewhat antiquated, requiring an end-user to try opening a .rar file in an attachment.. so tbh its a piece of gob for what it's supposed to do. That being said, if your target is using an older pc with unpatched itunes installed, and stupidly opening attachments... then they totally deserve the pwnage they get.

According to the company that makes fF "The FinFisher product portfolio is solely offered to Law Enforcement and Intelligence Agencies." Which basically amounts to third world Intelligence Agencies because any self respecting elite agency has their own tools and developers that are light years ahead in their intrusion and spying software.